from tkinter import *

master = Tk()

def test():
    if e1.get() == '小甲鱼':
        print('正确')
        return True
    else:
        print('错误！')
        e1.delete(0, END)
        return False

v = StringVar()

e1 = Entry(master, textvariable = v, validate = 'focusout', validatecommand = test)
e2 = Entry(master)
e1.pack(padx = 10, pady = 10)
e2.pack(padx = 10, pady = 10)

mainloop()
